Linux.FR has an interview with Lennart Poettering of PulseAudio and systemd fame (among others). Regarding PulseAudio: "I can understand why people were upset, but quite frankly we didn't really have another option than to push it into the distributions when we did. While PulseAudio certainly wasn't bug-free when the distributions picked it up the majority of issues were actually not in PulseAudio itself but simply in the audio drivers. PulseAudio's timer-based scheduling requires correct timing information supplied by the audio driver, and back then the drivers weren't really providing that. And that not because the drivers were really broken, but more because the hardware was, and the drivers just lacked the right set of work-arounds, quirks and fixes to compensate for it."

It seems that these topics are ignored by most except PA (and sometimes Lennart) haters. Because it works for most of people.
I call PA progress. Not to have to care about music player fighting with flash player just because the one likes to keep handle open (wasting power as well) is worthy. Yep, there is (was) dmix, but it also doesn't work everywhere and in fact does something similar to PA's job (and is a very cleverly made piece of software).

It was introduced early and therefore had bugs. This is normal in Linux. But it pays off. I don't have to think about audio issues on linux anymore, it just works out of the box as in other major OS's. For all that disagree, it is not mandatory.